Guiding appliance for drills.



No. 669,764. Patented Mar. [2, I90I. M. POTTER. GUIDING APPLIANCE FORDRILLS.

(Applicaticn filed Nov 27, 1900.)

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WTNESSES ml]IIIIIIIIIIHIIIIIIIIIHIIIIIIIIIIIIIHHIIIHI STATES PATENTFFICE.

MORGAN POTTER, OF FISHKILL-ON-THF-HUDSON, NEW YORK.

GUIDING APPLIANCE FOR DRILLS.

SPECIFICATION formingpart of Letters Patent No. 669,764, dated March 12,1901.

Application filed November 2'7, 1900. Serial No. 37.889. (No'modelJ Toall whom it may concern.-

Be it known that I, MORGAN POTTER, a citizen of the United States,residing at Fishkillon-the-I-Iudson, county of Dutchess, and State ofNew York, have invented certain new and useful Improvements in GuidingAppliances for Drills, of which the following is a full, clear, andexact specification, reference being had to the accompanying drawingsand to the letters of reference marked thereon.

My invention relates to drills, especially of the class employed forperforating metal, and preferably to the kind known as twistdrills,although my improvements may be found useful in connection withmetal-drills of other kinds.

The object of my invention is to provide or supply metal-drills withreliable and effective appliances whereby the drills will be enabled tobe used for accurately following or reboring a perforation already madein the metal, so that the new perforation will be exactly and accuratelyin line with the first and the drill prevented from dancing, chattering,or cutting out of true line.

To accomplish the foregoing object and to secure other and furtheradvantages in the matters of construction, operation, and use, myimprovements involve certain new and useful arrangements or combinationsof "parts and peculiarities of construction, all of which will be hereinfirst fully described and then pointed out in the claims.

In the accompanying drawings, forming part of this specification, Figure1 is a View in elevation of myimproved appliances constructed andarranged for operation in accordance with my invention and assembled asfor use, indicating in dotted lines the manner of applying a pair ofordinary calipers in order to guide the operator in the operation ofsharpening the drill. Fig. 2 is a section and elevation on a planethrough line m w of Fig. 1, showing the drill-guide in elevation. Fig. 3is a plan view of one of the drill-guides detached from the drill, thecylindrical portion of the guiding-block being smaller than in previousfigures to indicate that this portion may be of, any diameter smallerthan that of the drill, but larger than that of the shank of theguiding-block. Fig. 4 is a view similar to Fig. 3, but showing theguidingcylinder of diameter same as that of its shank.

In all the figures like letters of reference, wherever they occur,indicate corresponding parts.

A is the body of the drill, preferably of the form known as twist-drill,but under some circumstances other forms of drill might be substitutedfor this one or my improvements applied in connection with other forms.The shank of this drill a is shown as cylindrical and adapted to bereceived and held by any suitable form of chuck; but it may be fashionedotherwise than indicated in the drawings. The drill is perforatedaxially through and through, a portion of this perforation I) beingsmaller in diameter than the remaining portion, leaving a squareshoulder, as at c, at about the region of the union of the shank of thedrill with the other part.

B represents the cylindrical portion of the guide, the same being formedwith or applied on a shank O, which shank is fitted to closely occupythe larger portion of the bore through the drill and is of a length toabut against the shoulder c and hold the inner face of the cylindricalguide B a very trifle away from the cutting lips of the drill-say-. asixtyfourth of an inch-so that the cutting-lips will not be damaged ordulled thereby. The cylindrical shank O is planed off or cut away fornearly its entire length, leaving a narrow flat surface d, against whichthe end of the settingscrew bears to keep the shank and guide fromturning or moving from the seat provided for it when the drill is atwork.

D is the securingbolt, which is tapped through the body of the drill ata point well back from the cutting-lips, so that the drill may be groundaway practically for its entire length.

The outer extremity of the guide-cylinder is slightly beveled, asindicated at 6, so as to facilitate the insertion of the guide in thedrill-hole that is to be followed without difficulty and withoutdamaging the perforation or the guide.

In Fig. 4 the cylindrical guide at Binstead of being of greater diameterthan the shank C is of the same diameter, so that it may be entered in asmaller perforation. In this on the side toward the cutting-lips.

form the inner extremity of the cylindrical guide instead of beinglocated a trifling distance outside the limit of the cutting-lips shouldbe located a corresponding distance within the limit of these lips.

From the foregoing it will be seen that I propose to employ these guidesof any required or desired size from the diameter of the bore up to thatof the drill. They are preferably of hardened steel,so that they cannotbe worn by turningin the metal, as they must do while the drill isrevolved, and they are smooth on the exterior, so that they cannotenlarge the opening as the drill progresses, but will compel the drillto follow accurately in the axis of the opening.

These guides are employed in cases where accurate work is necessary ordesired. It is well known that ordinary metal drills following in aperforation already made will naturally bear toward one point or anotheras the variations in the metal will compel or permit or as the conditionof the cutting edges will compel or permit, and this is obviated bymyimproved guide.

It will be observed that the perforation through the drill is smallerindiameter than the smallest portion of the drill, so that the grooves arenot cut through to the weakening and damage of the drill. The purpose ofperforating the drill throughout its length is to permit the insertionof a drift at the back of the drill to drive out the shank 0 when it isnecessary to remove it for inserting a new or different guide or forgrinding the drill, and to prevent accumulation of foreign matterswithin the perforation, and to facilitate cleaning the perforation.

To facilitate gaging, I supply the drill with a groovef, leaving asquare or plain face 9 This face being turned perpendicular to the axisof the drill operates as a guide for one point of a pair ofcaliperssuch, for instance, as represented in dotted lines at E in Fig.1the other point of the calipers being made to determine the properlocation of the extremity of the cutting-lip, but the groovefand plainface 9 may be omitted.

In grinding the drill of course the guide B or B must be removed. Afterthe drill is ground the inner end of the shank C should becorrespondingly cut away or ground off, so that when the end abutsagainst the shoulder 0 the guide B or B will be in proper location. Itis for this reason that the plain surface 01 extends about the length ofthe shank 0; otherwise when the end of the shank is ground away theupper surface of it would also need to be ground.

I am aware that it has heretoforebeen proposed to locate a secondtwist-drill within a larger drill for the purpose of operating inconjunction-that is, so that in boring the first drill would cut a smallperforation while the larger one is cutting a larger perforation. Such adrill requires that the outer drill be cut through the grooves, and,besides, the smaller drill could not operate as a guide after the mannerof my improvement, for the reason that the edges of the grooves wouldcut and enlarge the first perforation, and thereby defeat the accurateboring of the larger perfo' ration, as is accomplished by my invention.

My improved appliances constructed and arranged as above set forth arefound in practice to admirably answer the purpose or object of theinvention hereinbefore alluded to. Involving nothing but circular work,they are easily, cheaply, and accurately made, and they are durable andefficient without interfering with the complete utilization of thedrill.

Having now fully described my invention, what I claim as new herein, anddesire to secure by Letters Patent, is

1. The herein-described cylindrical guide for drills, the same beingprovided with a shank and combined with a drill having an axialperforation smaller in diameter than the smallest part of the drill andextending throughout its length, said perforation being smaller indiameter at one portion than at the other, leaving aninner shoulderagainst which the said shank abuts, substantially as shown and setforth.

2. The herein-described cylindrical guide for drills, the same beingprovided with a shank having aflattened or cut-away portion as explainedand being combined with a drill having an axial perforation, an innershoulder, and a setscrew for holding the shank, substantially as shownand set forth.

3. The herein-described cylindrical guide fordrills, the same beingprovided with a beveled extremity and a shank having a flattened portionand combined with a drill having an axial perforation extendingthroughout its length, an inner shoulder againstwhich the shank of theguide abuts, and a set-screw for holding the shank, substantially asshown and set forth.

In testimony whereof I have signed my name to this specification in thepresence of two subscribing witnesses.

MORGAN POTTER.

Witnesses:

M. E. CURTISS, THOMAS ALDRIDGE.

